Prominent architectural projects using stainless steel include the Cheung Kong Centre in Hong Kong; the Canary Wharf development in London; China's tallest building, Jin Mao, in Shanghai; and one of the world's tallest buildings, the Petronas Towers in Kuala Lumpur. "In the decade ending in 2002, the value of stainless steel products used in the architectural, building and construction market grew from about $300 million to $1.2 to $1.6 billion," says Catherine Houska, senior development manager of Technical Marketing Resources, a specialty metals consulting firm.
Fashion is only one of the reasons for the increased use, says Houska. "Stainless steel is popular with some of the world's most well-known architects. It is an environmentally friendly material and a practical choice for many demanding long-term applications. There's no reason why it shouldn't last the life of the building or structure."
That sustainability makes stainless steel an ideal choice not only for building exteriors but also for applications such as street furniture. "You don't have to worry about there being enough corrosion so that [there is] structural deterioration that might make sitting on a park bench or leaning on a railing potentially hazardous," says Houska. "Corrosion can be avoided by selecting an appropriate stainless steel and finish," she notes. "Even if there is light corrosion, it could take hundreds or even thousands of years before it could structurally fail."
In addition, some architects are choosing stainless for its high strength. "The new seven World Trade Center building in New York, which is a Skidmore, Owings & Merrill project, is stainless steel and glass on the outside. The lobby is all stainless steel wall panels with some stainless steel security barriers. The storefronts are particularly interesting because they used an extremely high-strength stainless steel for security reasons," says Houska.
Practicality isn't overtaking aesthetics, however. "In other [applications] the choice has far more to do with aesthetics. For some exterior applications, it's all about the way it reflects light and the surroundings so that it looks blue on a sunny day or picks up the colors of the rainbow," says Houska.
As green building begins to pick up steam, "more architects and building owners consider the environmental impact of architectural metals across their entire product life cycle, including mining and manufacturing, during the building life and the potential for reuse and recycling," says Houska. "Because stainless steel can be recycled and remelted repeatedly without downgrading its use, 95 percent of stainless steel products are manufactured using recycled materials," she notes. "Additionally, it meets many of the standards for green materials established in the LEED Green Building Rating System."
Practical and friendly
"Our company produces stainless steel using a high percentage of recycled materials," adds Charles Turack, vice president and general manager of coil products for Outokumpu. "The effect that we have with our production on the environment is rated very low among industrial processes. On the back end, the product itself is considered very green because it is 100 percent recyclable, and it lasts a long time."
Stainless steel has been a growing market for Outokumpu in North America, says Turack. "We have been in the architectural curtain wall and panel market for about two decades, and our business in this segment has tripled since the year 2000. In the future, we don't see the growth staying at the rapid pace, but we do see a continuing use that mirrors the current rate.
"We are also planning for future growth in areas where stainless steel hasn't been used significantly, for example, bridges. Not necessarily the big multi-lane bridges that are part of interstate highways but smaller pedestrian bridges in cities and parks or two-lane traffic bridges in smaller communities, rural areas or parks."
Some recent projects that use Outokumpu stainless are the Hyatt Center and 111 S. Wacker Drive building, both in downtown Chicago, along with "our most notable recent one in Chicago's Millennium Park--the Cloud Gate sculpture known as the Bean," says Turack.
Cloud Gate, the 110-ton elliptical sculpture designed by British artist Anish Kapoor, measures 66 feet long by 33 feet high, and it is among the largest public art installations in the world. The sculpture consists of T316L stainless steel plate, which required more than 2,500 lineal feet of seam welds.
The stainless material of choice for facades in high-stress environments has been Outokumpu's 316L HyClad product range. "The HyClad product line has been used for exterior applications because it meets a lot of needs that the architect has when he looks to clad a building in stainless steel," says Turack. "The reflectivity is in a middle range, not too bright, but it's not dull. The corrosion resistance is high, depending on the alloy factors. It also has a smooth surface that is less likely to hold contaminants that occur naturally in the air.
"For architectural panels, we have taken special care throughout the production process to ensure good flatness, tolerances and product consistency," says Turack. "In particular, we guarantee matchability from sheet to sheet through the aid of an onsite viewing board where sheets can be erected and viewed for consistency (so the building exterior has a uniform appearance). In addition, before we commence delivery, we can supply full-size sample shipments to be approved by the fabricator, owner and architect," he notes.
When it comes to designing with stainless steel, costs are the first issue on the minds of many building owners. "Generally, if life cycle cost is considered and you are looking at either a high-traffic building or a building that will be in place for 50 years or more, then it becomes easy to justify stainless steel," says Houska.
Once stainless has been approved as the material for a new building, architects face the problem of choosing the right grade. If an improper grade of stainless is specified the effects can be costly, says Houska. "If the wrong stainless is exposed, for example, to coastal or de-icing salts and higher levels of urban or industrial pollution, then corrosion may appear within the first year. On the other hand, if the correct stainless steel and finish are selected and it is properly maintained, the material will remain attractive over the life of the building," she notes.
"We want to make sure architects understand which is the right grade to use in different environments," says Turack. He notes that Outokumpu makes its products and specifications available both online and in print. The company also sponsors and holds seminars and educational sessions for architects. "We make specific visits to architectural firms to answer their questions and make information available," says Turack. "We show them pictures of success and failure situations in which stainless steel was used in an exterior application."
A bright future
Houska believes that stainless steel use will continue to increase. "Certainly things that are fashion driven can go up and down. There are stages where everybody wants a stone building or a masonry building or a metal building," she says. "But when it comes to everyday applications, like bathroom partitions, countertops or railings, it will continue to grow."
This growth will give Outokumpu a platform for continuing its architectural education. "Over the last decade, Outokumpu has made significant inroads in the architecture, building and construction market in North America," says Turack. "Our objective moving forward is to continue to demonstrate to architects, specifiers, fabricators and our distributors the benefits of using Outokumpu stainless steel." MM
By Lauren Duensing, from the January 2006 issue of Modern Metals.